Control system for applying a pavement coating emulsion

ABSTRACT

A coating applicator vehicle is configured to selectively discharge a flow of liquid emulsion and aggregate onto a roadway. The vehicle includes a rolling chassis and a powered spraying assembly supported by the chassis. The spraying assembly includes a pump and a spray bar assembly. The vehicle also includes a control system with a speed sensor and a computer. The computer is operably connected to the pump to control a volumetric flow rate of coating material provided by the pump as a function of the sensed ground speed to apply coating material at a predetermined application rate.

RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application Ser.No. 62/108,273, filed Jan. 27, 2015, entitled PAVEMENT COATING SYSTEM,which is hereby incorporated in its entirety by reference herein.

BACKGROUND

1. Field

The present invention relates generally to road paving equipment. Morespecifically, embodiments of the present invention concern a pavementcoating system configured to spray a mastic material to a road.

2. Discussion of Prior Art

Paving construction and repair vehicles have long been used to dispenseone or more types of flowable pavement coating materials onto anexisting roadway. For instance, conventional paving vehicles are wellknown for laying, spreading, and screeding a layer of bituminous asphaltonto a roadway. Other conventional vehicles comprise a distributingvehicle that is configured to spray a liquified tack coat material ontoan existing asphalt road surface.

Yet further, other known vehicles are configured to spray a frictionmastic material that includes a liquid asphalt emulsion, aggregate, andone or more polymers. The mastic mixture is generally sprayed onto thesurface of a paved road to extend the usable life of the road.

However, conventional paving construction and repair vehicles havevarious deficiencies. For instance, conventional vehicles that sprayfriction mastic material are difficult and expensive to use. Forexample, these conventional vehicles generally carry a large volume ofmastic material that must be strained during the spraying process toseparate aggregate particles and congealed clumps of material from themastic to be sprayed and to store the separated particles and clumps ina straining basket. The process of removing the separated particles andclumps from the vehicle is notoriously time consuming and requires theuse heavy machinery to lift and move the basket and material from thevehicle.

Another deficiency associated with conventional distributing vehicles isthat sprayed material is easily wasted because of the difficultlyassociated with positioning and advancing the vehicle. For instance, thespray boom of prior art distributing vehicles is difficult to alignprecisely with the side margin of the roadway.

SUMMARY

The following brief summary is provided to indicate the nature of thesubject matter disclosed herein. While certain aspects of the presentinvention are described below, the summary is not intended to limit thescope of the present invention.

Embodiments of the present invention provide a pavement coating systemthat does not suffer from the problems and limitations of the prior artmaterial distributing vehicles set forth above.

A first aspect of the present invention concerns a method of using acoating applicator vehicle to apply a flow of pavement coating materialonto a roadway at a predetermined application rate, where the materialincludes a liquid emulsion and aggregate. The method broadly includesthe steps of setting the predetermined application rate; as the vehicleis being advanced, determining the ground speed of the vehicle; and asthe vehicle is being advanced, operating a pump to discharge the flow ofpavement coating material onto the roadway through a series of spraynozzles. The step of operating the pump includes the step of maintainingthe predetermined application rate by adjusting the volumetric flow rateof the pump in response to a change in the determined ground speed.

A second aspect of the present invention concerns a coating applicatorvehicle configured to selectively discharge a flow of pavement coatingmaterial onto a roadway at a predetermined application rate, where thematerial includes a liquid emulsion and aggregate. The coatingapplicator vehicle broadly includes a rolling chassis, a poweredspraying assembly, and a control system. The rolling chassis is operableto be advanced in a forward direction along the roadway. The sprayingassembly is supported by the rolling chassis and extends transversely tothe forward direction to selectively discharge coating material along alateral direction. The spraying assembly includes a pump and a spray barassembly. The spray bar assembly includes a plurality of spray nozzlesthat selectively fluidly communicate with the pump to receive a flow ofcoating material from the spray boom and to discharge the flow ofcoating material. The spray nozzles cooperatively define a sprayapplication pattern along which the roadway is wetted with coatingmaterial, with the pattern presenting a width dimension measuredtransverse to the forward direction. The control system includes a speedsensor and a computer operably connected to the speed sensor to sense aground speed of the vehicle. The computer is operably connected to thepump to control a volumetric flow rate of coating material provided bythe pump as a function of the sensed ground speed to apply coatingmaterial at the predetermined application rate.

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the detaileddescription. This summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter. Other aspectsand advantages of the present invention will be apparent from thefollowing detailed description of the embodiments and the accompanyingdrawing figures.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

Preferred embodiments of the invention are described in detail belowwith reference to the attached drawing figures, wherein:

FIG. 1 is a rear perspective of a coating applicator vehicle constructedin accordance with a preferred embodiment of the present invention;

FIG. 2 is a fragmentary rear perspective of the coating applicatorvehicle shown in FIG. 1, showing a spray bar assembly of the vehicle;

FIG. 3 is a rear elevation of the spray bar assembly shown in FIGS. 1and 2;

FIG. 4 is a fragmentary top view of the spray bar assembly shown inFIGS. 1-3;

FIG. 5 is a fragmentary upper rear perspective of the spray bar assemblyshown in FIGS. 1-4;

FIG. 6 is a fragmentary lower front perspective of the spray barassembly shown in FIGS. 1-5, showing a central boom section and oppositeextendable boom sections, with the extendable boom sections being in aretracted position;

FIG. 7a is a fragmentary upper perspective of the spray bar assemblyshown in FIGS. 1-6, showing the extendable boom section on the rightside of the vehicle shifted laterally outboard to an extended position;

FIG. 7b is a fragmentary upper perspective of the spray bar assemblyshown in FIGS. 1-7 a, showing the extendable boom section on the leftside of the vehicle shifted laterally outboard to an extended position;

FIG. 8 is a fragmentary cross section of the spray bar assembly shown inFIGS. 1-7 b;

FIG. 9 is an exploded rear perspective of the spray bar assembly shownin FIGS. 1-8;

FIG. 10 is a side elevation of the coating applicator vehicle shown inFIG. 1, showing the spray bar assembly shifted into a lower position;

FIG. 11 is a side elevation of the coating applicator vehicle similar toFIG. 10, but showing the spray bar assembly shifted into an upperposition;

FIG. 12 is a fragmentary front perspective of the coating applicatorvehicle shown in FIGS. 1, 10, and 11, showing a storage tank mounted onthe chassis of the vehicle, and further showing a suction strainerassembly, pressure strainer assembly, and pump of the vehicle;

FIG. 13 is a fragmentary front elevation of the coating applicatorvehicle shown in FIGS. 1 and 10-12, showing the suction strainerassembly and pump mounted on the chassis and arranged verticallyrelative to each other;

FIG. 14 is a fragmentary top view of the coating applicator vehicleshown in FIGS. 1 and 10-13, showing the strainer assemblies in fluidcommunication with the storage tank and in fluid communication withhoses of the spray bar assembly;

FIG. 15 is a fragmentary cross section of the coating applicator vehicletaken along line 15-15 in FIG. 13;

FIG. 16 is a greatly enlarged view of the spray bar assembly shown inFIGS. 1-9, showing the central boom section, one of multiple valvesmounted on the central boom section, one of multiple spray nozzlesattached to and fluidly communicating with the valve, and one ofmultiple valve cylinders supported on the central boom section andoperably coupled to the valve;

FIG. 17 is a schematic view of a control system of the coatingapplicator vehicle shown in FIGS. 1-16; and

FIG. 18 is a fragmentary perspective of the control system shown in FIG.17, showing a user interface device of the control system.

The drawing figures do not limit the present invention to the specificembodiments disclosed and described herein. The drawings are notnecessarily to scale, emphasis instead being placed upon clearlyillustrating the principles of the preferred embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning initially to FIG. 1, a coating applicator vehicle 20 isconstructed in accordance with a preferred embodiment of the presentinvention. The illustrated vehicle 20 is preferably used to apply afriction mastic material (not shown) to the surface of a paved road (notshown). In the usual manner, the friction mastic material operates toextend the usable life of a paved asphalt road (or other road surfaces).The friction mastic material preferably comprises a mixture including aliquid emulsion (e.g., an asphalt emulsion), aggregate, and one or morevarious polymers. However, the friction mastic could be variouslyconfigured within the scope of the present invention.

It will also be appreciated that the depicted vehicle 20 could be usedto dispense one or more other types of flowable pavement coatingmaterials. For instance, the vehicle 20 could be configured to spray atack coat material (e.g., onto an existing asphalt surface). The vehicle20 preferably includes a rolling chassis 22, a cab 24, a drive train(not shown), a storage tank 26, and a spraying assembly 28.

The rolling chassis 22 is conventional and includes an elongated chassisframe 30 and wheels 32 mounted on the chassis frame 30. The chassisframe 30 extends longitudinally to present front and back ends 34,36.The chassis frame 30 supports the cab 24 at the front end 34, a reardeck 38 at the back end 36, and the storage tank 36 between the frontand back ends 34,36. The rear deck 38 is preferably fixed to the backend 36 of the chassis frame 30. As will be discussed, a spray barassembly 40 is preferably attached to and supported by the rear deck 38adjacent the back end 36 of the frame 30. In the usual manner, thevehicle 20 is advanced along a forward direction F while spraying theflowable pavement coating material along a lateral application spraypattern P (see FIG. 4).

As will be discussed in greater detail, the spraying assembly 28 isoperable to pump flowable pavement coating material from the tank 26,strain the pumped material, and dispense the material onto the roadway.The spraying assembly 28 preferably includes the spray bar assembly 40,suction and pressure strainer assemblies 42,44, and pump 46.

Spray Bar Assembly

Turning to FIGS. 2-11 and 16, the spray bar assembly 40 extendstransversely to the forward direction F of the vehicle 20 and isoperable to spray the flowable pavement coating material onto thepavement. The spray bar assembly 40 preferably includes a spray boom 48and a spray bar frame 50 that supports the spray boom 48 for verticaland lateral movement relative to the chassis 22.

The spray bar frame 50 is preferably shiftable vertically, relative tothe rolling chassis 22 along an upright direction. The spray bar frame50 is preferably configured to support the spray boom 48 relative to therolling chassis 22 and to selectively position the spray boom 48vertically above the pavement. The spray bar frame 50 includes anelongated slider housing 52 that extends laterally, mounting collars 54attached to the slider housing 52, and a boom shift cylinder 56 (seeFIGS. 2 and 3). The slider housing 52 preferably includes an elongatedtubular body 58 and a pair of depending arms 60 mounted on respectiveends of the body 58.

The mounting collars 54 are interconnected by an elongated collarbracket (not shown). Each collar 54 presents a smooth, generally squarebore that slidably receives the tubular body 58. Thus, the collars 54are preferably permitted to slide laterally relative to the tubular body58. Because the spray boom 48 interconnects the arms 60, both the arms60 and the spray boom 48 can move laterally relative to the chassis 22of the vehicle 20. This slider mechanism preferably permits the entirespray boom 48 to slide laterally (also referred to as “side shift”).

The slider mechanism preferably allows the entire spray boom 48 to slidea distance S from a centered position to one laterally endmost shiftposition. The distance S is preferably about ten inches (10″). Thus, thetotal lateral travel of the spray boom 48 from one laterally endmostshift position to the opposite laterally endmost shift position ispreferably about twenty inches (20″). However, the illustrated slidermechanism could allow either a smaller or greater amount of lateral boomtravel.

The boom shift cylinder 56 includes a cylinder housing 62 and a piston64. The cylinder housing 62 is fixed to the collar bracket (not shown)that extends between the collars 54. The piston 64 of the boom shiftcylinder 56 is drivingly attached to one end of the tubular body 58.Extension and retraction of the piston 64 causes the tubular body 58 toslide through the collars 54. Thus, movement of the piston 64 causes thetubular body 58 and the spray boom 48 to shift laterally relative to thechassis 22 of the vehicle 20.

This mechanism for lateral shifting of the spray boom 48 is preferred sothat the entire spray boom 48 can be precisely laterally positionedrelative to the pavement (e.g., to align one end of the spray boom 48with an edge of the pavement) without having to change the lateralposition of the vehicle 20. This mechanism also permits the spray boom48 to be laterally aligned with the pavement without having to adjustthe width of the spray boom 48.

The boom shift cylinder 56 is conventional and preferably comprises ahydraulic cylinder. However, an alternative drive motor (such as analternative hydraulic cylinder) could be used to shift the entire sprayboom 48. Furthermore, it will be appreciated that other components ofthe lateral shifting mechanism could be alternatively configured toshift the spray boom 48 laterally. Yet further, for some aspects of thepresent invention, the vehicle 20 could be devoid of a mechanism toshift the entire spray boom 48 laterally relative to the vehicle 20.

Turning to FIGS. 2, 10, and 11, the spray bar assembly 40 alsopreferably includes a linkage 66 to mount the spray bar frame 50rearwardly of the chassis frame 30. In particular, the spray barassembly 40 is preferably attached to and supported by the rear deck 38.As a result, the spray bar assembly 40 is spaced rearwardly of the backend 36 of the frame 30. The linkage 66 preferably includes a pair ofrigid links 68, a pair of turnbuckle links 70, a pair of collar supportbrackets 72, and a pair of frame mounting brackets 74. Each link 68,70is pivotally attached at an aft end thereof to one of the supportbrackets 72. The support brackets 72 are attached to corresponding onesof the collars 54.

The links 68 each present a fixed length. However, the turnbuckle links70 each comprise a turnbuckle mechanism to adjust the length of theturnbuckle link 70. However, the fixed link 68 and/or turnbuckle links70 could be alternatively configured without departing from the scope ofthe present invention.

The forward ends of the links 68,70 are pivotally attached to mountingbrackets 74 fixed to the frame 30. Thus, the links 68,70, supportbrackets 72, mounting brackets 74, and spray bar frame 50 cooperativelyform a four-bar linkage that permits the spray bar frame 50 to shiftvertically relative to the chassis frame 30.

The illustrated spray bar assembly 40 also includes a hanger frame 76that is operable to support the spray bar frame 50 and other equipment(such as material hoses). The hanger frame 76 includes a pair of hangerarms 78 and a lateral beam 80 (see FIG. 1) that interconnects the hangerarms 78. A forward end of each hanger arm 78 is pivotally attached tothe chassis frame 30 above the spray bar frame 50 so that the hangerframe 76 can pivot vertically about a lateral pivot axis.

The hanger frame 76 further includes hanger links 82 that interconnectthe hanger frame 76 and the spray bar frame 50. In particular, upperends 84 of each hanger link 82 are pivotally attached to thecorresponding hanger arm 78 between the ends thereof (see FIGS. 10 and11). Lower ends 86 of each hanger link 82 are pivotally attached to thesupport brackets 72 of the spray bar frame 50 (see FIGS. 10 and 11).Thus, pivotal up-and-down movement of the hanger frame 76 causescorresponding vertical movement of the spray bar frame 50.

Preferably, the spray bar assembly 40 and the hanger frame 76 areremovably mounted with quick-connect pins 88 that permit the spray barassembly 40 to be quickly attached and removed from the vehicle 20 (seeFIG. 5). Specifically, the links 68,70 are pivotally attached to thebrackets 72,74 with quick-connect pins 88. The hanger links 82 areconnected to the support brackets 72 and the hanger arms 78 withquick-connect pins 88 (see FIGS. 10 and 11). Also, the hanger arms 78are connected to the chassis frame 30 and to a hydraulic lift cylinder90 with quick-connect pins 92 (see FIGS. 10 and 11). The illustratedpins 92 preferably include threaded bolts, but alternative pin fastenerscould be used to provide a quick-connection arrangement.

The spray bar assembly 40 further includes the hydraulic lift cylinder90 to provide a motor operable to shift the spray bar frame 50 and thespray boom 48 vertically relative to the rolling chassis 22. The liftcylinder 90 includes a cylinder housing 94 and a piston 96. The cylinderhousing 94 is mounted to the chassis frame 30 so that the piston 96extends longitudinally along and projects rearwardly of the chassisframe 30. The end of the piston 96 is pivotally attached to one of thehanger arms 78 at a pivot joint 98 spaced from the ends of the onehanger arm 78. Thus, as the piston 96 is hydraulically extended andretracted relative to the housing 94, the hanger frame 76correspondingly pivots up and down relative to the chassis frame 30.Consequently, extension and retraction of the piston 96 preferablycauses corresponding up and down vertical shifting movement of the spraybar frame 50 and the spray boom 48. The lift cylinder 90 is preferablyconventional and comprises a hydraulic cylinder, although an alternativepowered motor could be used to selectively raise and lower the spray barassembly 40.

Turning to FIGS. 2-11 and 16, the spray boom 48 preferably includes acentral boom section 100 and extendable boom sections 102 slidablyattached to the central boom section 100 with a slide mechanism 104. Theslide mechanism 104 includes channels 106 and slides 108 (see FIGS. 8and 9), with the channels 106 being fixed to corresponding boom sections100,102. The boom sections 100,102 are preferably hollow and presentcorresponding elongated chambers 110 a,b (see FIG. 8) and chamber inlets112 a,b (see FIGS. 2 and 5). The boom sections 100,102 also preferablypresent drain outlets 114 a,b (see FIG. 6), access openings 115 a,b, andplugs 116 removably inserted in the outlets 114.

The illustrated spray boom 48 is preferably configured so that the boomsections 100,102 extend along a common lateral direction and aregenerally parallel to one another and to the common lateral direction.However, it is within the scope of the present invention where one ormore of the boom sections 100,102 is alternatively positioned.

Preferably, the slide mechanism 104 permits the extendable boom sections102 to slide relative to the central boom section 100 along the commonlateral direction. In the illustrated embodiment, the boom sections 102are preferably slidable between a retracted position (see FIGS. 2-6) andan outermost deployed position (see FIGS. 7a and 7b ) such that thespray boom 48 has an adjustable boom width B (see FIG. 1). In theretracted position, the extendable boom sections 102 overlapcorresponding portions of the central boom section 100, with the boomsections 100,102 cooperatively defining a minimum boom width dimension.In the outermost deployed position, the extendable boom sections 102 areshifted in opposite outboard directions to project laterally outboardfrom lateral ends of the central boom section 100. It will also beappreciated that each boom section 102 can be shifted outboard from theretracted position to any deployed position located between theretracted position and the outermost deployed position.

For some aspects of the present invention, the boom sections 100,102could be alternatively shiftably attached to one another. For instance,the extendable boom sections 102 could be pivotally mounted relative tothe central boom section 100 so that the boom sections 102 are swingablerelative to the central boom section 100 (e.g., between a retractedposition and an outermost deployed position).

The chamber inlets 112 a,b are preferably fluidly connected tocorresponding supply hoses 118 a,b (see FIGS. 2 and 14). Each chamber110 is operable to receive the coating material and distribute thecoating material laterally along the width of the corresponding boomsection 100,102. However, it is within the scope of the presentinvention where the boom sections 100,102 are alternatively configuredto carry and distribute the coating material. For instance, each boomsection 100,102 could have a hose (not shown), located internally orexternally relative to the boom section 100,102, to distribute coatingmaterial along the width of the boom section 100,102. As will bediscussed, each boom section 100,102 is configured to supply coatingmaterial to corresponding spray nozzles 120.

Again, the extendable boom sections 100,102 are slidable betweenretracted and outermost deployed positions such that the spray boom 48has an adjustable boom width B (see FIG. 1). In the illustratedembodiment, the boom width B is preferably adjustable from about eightfeet (8 ft) in the retracted position to about eighteen feet (18 ft) inthe outermost deployed position. In the outermost deployed position, thespray nozzles 120 preferably spray material so that the sprayapplication pattern P has a maximum spray width A (see FIG. 4) of abouttwenty feet (20 ft). However, it is within the scope of the presentinvention where the spray boom 48 has an alternative range of boom widthB and/or spray width A. Also, for some aspects of the present invention,the spray boom 48 could have a fixed boom width.

In the retracted position, the vehicle 20 preferably presents a maximumvehicle width that is less than two and one half meters (2.5 m), whichis the maximum legal vehicle width allowed by law in a number of foreigncountries.

Referring again to FIGS. 2-11 and 16, the spray bar assembly 40preferably includes the spray nozzles 120, valves 122, and valvecylinders 124 (see FIGS. 5 and 6). In the usual manner, the spraynozzles 120 are operable to spray the flowable pavement coating materialonto the pavement. Each boom section 100,102 preferably supports andsupplies material to a plurality of spray nozzles 120 along the width ofthe boom section 100,102. The spray nozzles 120 fluidly communicate witha corresponding one of the chambers 110 to receive a flow of coatingmaterial from the spray boom 48 and discharge the coating material. Itwill be appreciated that one or more of the boom sections 100,102 couldhave an alternative number and/or configuration of spray nozzles 120.

Each valve 122 preferably comprises a ball valve although, for someaspects of the present invention, the valves 122 could be alternativelyconfigured to selectively fluidly interconnect the chamber 110 and thecorresponding nozzle 120. Each spray nozzle 120 is preferably fluidlyconnected to the chamber 110 a,b of the corresponding boom section100,102 by one of the valves 122. Thus, the flow of coating materialthrough each spray nozzle 120 is preferably controlled by thecorresponding valve 122 (i.e., by opening or closing the valve 122).

Each spray nozzle 120 preferably discharges coating material in agenerally planar fan pattern. The illustrated spray nozzles 120 eachpresent an orifice (not shown) with an orifice diameter dimension thatranges from about five sixteenths of an inch ( 5/16″) to about one halfof an inch (½″) and, more preferably, is about three eighths of an inch(⅜″). The orifice diameter dimension is preferably about twice the sizeof the maximum aggregate size allowed by the strainer systems of thevehicle 20 to pass to the spray boom 48. Thus, because the strainerassemblies preferably permit a maximum aggregate size of about threesixteenths of an inch ( 3/16″) to pass through to the spray boom 48, themore preferred orifice diameter dimension is about three eighths of aninch (⅜″).

Each spray nozzle 120 preferably discharges the coating material in agenerally planar fan pattern that impinges the roadway along a laterallyextending spray line L (see FIG. 4). To discharge coating material inthe form of a generally planar fan pattern, the spray nozzle 120preferably includes an endmost ledge that redirects material flow fromthe orifice in a downward direction.

The illustrated spray nozzles 120 are preferably arranged so that thespray line L is at an acute angle relative to the common lateraldirection of the boom sections 100,102. In other words, the spraynozzles 120 are preferably arranged so that a line perpendicular to thespray line L and the forward direction F cooperatively define an acutespray angle α (see FIG. 4). The spray angle α preferably ranges fromabout five degrees (5°) to about ten degrees (10°) and, more preferably,is about eight degrees (8°). However, for some aspects of the presentinvention, the nozzle orientation could fall outside of the preferredrange.

The spray nozzles 120 are also preferably oriented so that the spraylines L associated with each boom section 100,102 are generally parallelto one another. For instance, the spray lines L produced by the spraynozzles 120 of the central boom section 100 are generally parallel toeach other. Thus, for each boom section 100, adjacent pairs of spraynozzles form spray lines L that define an offset distance D (see FIG.4). It has been found that the illustrated offset distance D permits theplanar fan patterns of each spray nozzle 120 to overlap one anotherwithout causing the fan patterns to interfere with one another. Thespray nozzles 120 are preferably positioned and configured so that theoffset distance D ranges from about one inch (1″) to about four inches(4″), although the offset distance D could fall outside of this range.

The spray nozzles 120 each preferably present a maximum fan widthdimension W_(s) (see FIG. 4) that ranges from about thirty inches (30″)to about forty inches (40″) and, more preferably, is about thirty-sixinches (36″). While the illustrated configuration of spray nozzles 120is preferred, an alternative nozzle configuration could be used with theillustrated spray bar assembly 40.

The spray nozzles 120 associated with each of the boom sections 100,102are preferably spaced in series to form a corresponding lateral line ofspray nozzles 120 (see FIG. 4). The lateral lines of spray nozzles 120for the extendable boom sections 102 are preferably located forwardly ofthe extendable boom sections 102. Also, the lateral line of spraynozzles 120 for the central boom section 100 is preferably locatedrearwardly of the central boom section 100. This arrangement of spraynozzles 120 permits the extendable boom sections 102 to at least partlyoverlap corresponding portions of the central boom section 100 (e.g.,when the boom sections 102 are in the retracted position). However, thespray nozzles 120 could be alternatively positioned relative to boomsections 100,102 without departing from the scope of the presentinvention.

Preferably, the lateral lines of spray nozzles 120 are generallyparallel to one another and substantially perpendicular to the forwarddirection F. Furthermore, each lateral line of spray nozzles 120 in theillustrated embodiment is substantially parallel to the correspondingboom section 100,102 that supports and fluidly communicates the spraynozzles 120. However, it is within the scope of the present inventionthe lateral lines of spray nozzles 120 are alternatively oriented.

The spray nozzles 120 are preferably positioned so that adjacent spraynozzles 120 cooperatively define a spacing dimension W (see FIG. 4) thatranges between about twelve inches (12″) and about thirty inches (30″)and, more preferably, is about eighteen inches (18″). For theillustrated invention, it is also preferable that the maximum fan widthdimension W_(s) is about twice the length of the spacing dimension W.

Again, the spray bar assembly 40 preferably includes valve cylinders 124to control opening and closing of the valves 122. In the usual manner,each valve cylinder 124 includes a cylinder housing 126 and an elongatedpiston 128 (see FIG. 16). The valve cylinders 124 are conventional andpreferably comprise a hydraulic cylinder. However, an alternativepowered motor could be used to shift the valves between open and closedpositions.

For the central boom section 100, each valve 122 is operably connectedto one of the valve cylinders 124. More particularly, the housing 126 ofeach valve cylinder 124 is pivotally attached to the central boomsection 100, with the piston 128 being pivotally attached to a handle130 of the valve 122 (see FIG. 16). As the piston 128 extends andretracts, the valve handle 130 opens and closes the valve 122. Thus, forthe central boom section 100, the valves 122 are preferably opened andclosed independently of one another. However, it is within the ambit ofthe present invention where the spray bar assembly 40 is configured sothat the valves 122 of the central boom section 100 are operably linkedtogether (e.g., using a mechanical linkage or an electronic control) soas to open and close at the same time.

The spray bar assembly 40 also includes valve links 132 a,b (see FIGS.6, 7 a, and 7 b) associated with respective extendable boom sections102. Specifically, each valve link 132 is pivotally attached to thevalve handles 130 of the corresponding extendable boom section 102 atpivots 134. Preferably, each valve link 132 is configured so that thevalve handles 130 are simultaneously opened and simultaneously closed.While the illustrated valve link 132 is preferred to open and close thevalves 122 simultaneously, it is within the scope of the presentinvention where an electronic controller is used instead of themechanical linkage to provide simultaneous opening and closingoperation. Also, it is within the ambit of the present invention wherethe spray bar assembly 40 is configured so that the valves 122 of theextendable boom sections 102 can be opened and closed independently ofone another.

For each of the extendable boom sections 102, the valve cylinder 124 isoperably connected to the valve handle 130 of a middle one of the valves122. Specifically, the housing 126 of each valve cylinder 124 ispivotally attached to the corresponding extendable boom section 102,with the piston 128 being pivotally attached to the valve handle 130 ofthe middle valve 122. Thus, as the piston 128 of a corresponding boomsection 102 extends and retracts, the associated valve handles 130 openand close the respective valves 122 at the same time.

The spray bar assembly 40 further includes boom extension cylinders 136that are used to selectively extend and retract the extendable boomsections 102 (see FIGS. 5-7 b). Again, the extendable boom sections 102are slidable between a retracted position (see FIGS. 5 and 6) and anextended position (see FIGS. 7a and 7b ). The extension cylinders 136each include a cylinder housing 138 and a piston 140 slidable into andout of the housing 138. The housing are fixed relative to the centralboom section 100. Each piston 140 is attached to a bracket 142 (seeFIGS. 5 and 6) of the corresponding extendable boom section 102. Thus,as each piston 140 slides out of the housing 138 and into the housing138, the corresponding extendable boom section 102 is extended andretracted. Consequently, the extendable boom sections 102 are preferablymovable independently of one another. The extension cylinders 136 areconventional and preferably comprise a hydraulic cylinder. However, thespray bar assembly 40 could be alternatively configured to extend andretract the spray boom 48. For instance, the spray bar assembly 40 coulduse a single extension cylinder 136 to extend and retract both of theextendable boom sections 102.

When the spray boom 48 is in the retracted position, spray nozzles 120of the extendable boom sections 102 are substantially laterally alignedwith the spray nozzles 120 of the central boom section 100. Thus, whenretracted, the valves 122 of the extendable boom sections 102 arepreferably closed (i.e., so that only the valves 122 of the central boomsection 100 are open). This configuration is preferred to avoid applyingtoo much coating material on any area of the pavement.

When the spray boom 48 is in the extended position, the valves 122 ofthe boom sections 102 can all be opened. Because of the locations ofspray nozzles 120 in the extended position, the spray nozzles 120 areall operated to provide uniform coverage of coating material.

When one of the extendable boom sections 102 is intermediately locatedbetween the extended and retracted positions, the valves 122 of theextendable boom section 102 are all opened. At the same time, at leastone of the valves 122 of the central boom section 100 is closed,depending how much the extendable boom section overlaps the central boomsection. For instance, if the extendable boom section 102 isintermediately positioned so that an inboard one of the spray nozzles120 of the extendable boom section 102 is laterally aligned with anoutboard one of the spray nozzles 120 of the central boom section 100,the valve 122 corresponding to the outboard spray nozzle 120 of thecentral boom section 100 is closed. Similarly, if the extendable boomsection 102 is intermediately positioned so that two inboard spraynozzles 120 of the extendable boom section 102 are laterally alignedwith two outboard nozzles 120 of the central boom section 100, thevalves 122 corresponding to the outboard spray nozzles 120 of thecentral boom section 100 are closed. This configuration is preferred soas to avoid applying too much coating material on any area of thepavement.

In the illustrated embodiment, selective opening and closing of thevalves 122 of the central boom section 100 when one or both of theextendable boom sections 102 are in an intermediate position can be donemanually by the operator. However, as will be discussed, the sprayingassembly 28 preferably includes a control system 144 (see FIG. 17) toautomatically close valves 122 of the central boom section 100 (e.g., soas to turn off one of a pair of laterally overlapping spray nozzles120).

Pump, Strainer, and Material Transfer Components

Turning to FIGS. 12-15, the spraying assembly 28 preferably includes thesuction strainer assembly 42, the pressure strainer assembly 44, and thepump 46. As will be discussed, the pump 46 is configured draw coatingmaterial from the tank 26 and to move coating material through thestrainer assemblies 42,44 to strain the coating material. The strainedcoating material is then operable to be pumped through the supply hoses118 a,b connected to each of the boom sections 100,102 and to the boomsections 100,102.

The pump 46 preferably comprises a progressive cavity pump powered by ahydraulic motor 150. The pump 46 has an operating pressure that ispreferably greater than about twenty pounds per square inch (20 psi) andpreferably less than about fifty pounds per square inch (50 psi).Although the configuration of the illustrated pump 46 is operable topump material at greater pressures, the spraying assembly 28 of thepresent invention is efficiently configured to operate even when thepump 46 discharges material at relatively low pressures, preferably lessthan fifty pounds per square inch (50 psi). While the spraying assembly28 preferably uses the illustrated progressive cavity pump to pumpcoating material, it is within the ambit of the present invention wherean alternative pump (such as a piston pump) is used. However, theprogressive cavity pump has been found to be more durable than otherpumps. The pump 46 preferably defines a pump inlet 152 and a pump outlet154 (see FIG. 12).

The illustrated pump 46 is preferably calibrated to pump a known volume(or mass) of material for one complete pump revolution. Because thecontrol system 144 is programmed to retain the calibrated ratio ofpumped material volume (or mass) per revolution of the pump (a singlepump revolution is also referred to as a “pump count” or “count”), theprocessor can calculate the volumetric flow rate (and/or mass flow rate)of material transmitted by the pump 46. Thus, the pump 46 is preferablycalibrated so that a range of volumetric flow rates (and/or mass flowrates) of the pump 46 are associated with a corresponding range of pumpcounts. Preferably, the pump 46 is calibrated so that the error in theactual pump mass flow rate per count produced by the pump 46 (comparedto the expected mass flow rate per count) is less than two percent (2%).

The pump 46 is preferably configured to be calibrated withoutdischarging pavement coating material from the spray nozzles 120.Instead, the spraying assembly 28 includes an auxiliary hose (not shown)that is removably fluidly connected relative to the pump 46 so that thepump outlet 46 fluidly communicates with the auxiliary hose. The pump 46can be operated by the control system 144 to discharge, while operatingat a set rotational speed, a volume of material into a container (notshown) for a predetermined number of pump counts. The mass of materialin the container is then measured (e.g., by weighing the container andmaterial). The material can then be returned to the tank 26 or anotherstorage container.

This process is preferably repeated several times to discharge andmeasure the output volumes (mass) of the pump 46. As a result, thecalibration process produces a calibration scale factor to be used atany pump rotational speed to calculate the output volume (mass) ofpavement coating material.

The suction strainer assembly 42 preferably includes a fluid manifold156 and two (2) suction strainer baskets 158 (see FIG. 15). However, thesuction strainer assembly 42 could include an alternative number ofbaskets 158. For instance, the suction strainer assembly 42 couldinclude more than two (2) baskets 158. The availability of multiplestrainer baskets 158 permits continued operation of the sprayingassembly 28 when one of the baskets 158 becomes full of aggregate andcongealed coating material (and restricts substantially all materialflow through the basket 158). If an alternative suction strainerincludes more than two (2) baskets, the spraying assembly could continueto operate if multiple baskets become full of material (provided that atleast one basket is not full of material and permits material flowthrough the basket).

The fluid manifold 156 presents a strainer inlet 160 and strainer outlet162 of the suction strainer assembly 42 (see FIG. 14). The fluidmanifold 156 also presents upstream and downstream chambers 164,166 onopposite sides of the baskets 158 (see FIG. 15).

The fluid manifold 156 includes a diverter 167 that presents thestrainer inlet 160 and fluidly communicates with two (2) passages 168 ofthe manifold 156 (see FIG. 15). Thus, the chambers 164,166 fluidlycommunicate with each other and with the strainer inlet 160 via thediverter 167. The chambers 164,166 also fluidly communicate with thestrainer outlet 162.

The passages 168 preferably extend between the chambers 164,166 inparallel with one another. That is, the passages 168 provide twoseparate paths for fluid to move between the strainer inlet 160 and thestrainer outlet 162.

The suction strainer baskets 158 each preferably include a mesh body 170and a handle 172 (see FIG. 15). The mesh body 170 includes a side wall170 a and a bottom wall 170 b. The illustrated walls 170 a,170 b eachcomprise a mesh material that presents a plurality of openings. Theopenings each define an opening size dimension that preferably rangesfrom about one eighth inch (⅛″) to about three eights of an inch (⅜″)and, more preferably, is about one quarter inch (¼″). The walls 170a,170 b cooperatively define a basket chamber 173 a (see FIG. 12). Thebaskets 158 each preferably present an open top 173 b through which theflow of coating material passes into the basket chamber 173 a (see FIG.12).

The basket chamber 173 a of each basket 158 preferably defines a basketvolume dimension that ranges from about one gallon to about fivegallons. However, for some aspects of the present invention, the basketvolume could fall outside of this range.

The suction strainer baskets 158 are removably mounted in the fluidmanifold 156 (see FIG. 15). More specifically, each strainer basket 158is secured in a corresponding one of the passages 168 so that fluid mustflow through at least one of the strainer baskets 158 to pass betweenthe chambers 164,166. The fluid manifold 156 includes strainer covers174 that can be selectively removed to permit the strainer baskets 158to be accessed and removed from the fluid manifold 156 (e.g., to permitcleaning of the strainer basket 158 and/or the inside of the fluidmanifold 156). Each of the illustrated strainer baskets 158 ispreferably removable independently of the other strainer basket 158.

The fluid manifold 156 and each strainer basket 158 cooperatively definea manifold axis A1 along which the strainer basket 158 is manuallyslidable into and out of the passage 168 (see FIGS. 12 and 15). In theillustrated embodiment, the manifold axis A1 is preferably angledupwardly from the lateral direction at an acute angle θ (see FIG. 13) sothat an upper margin of the fluid manifold 156 is positioned outboardfrom a lower margin of the fluid manifold 156. The acute angle θpreferably ranges from about ten degrees (10°) to about fifty degrees(50°) and, more preferably, ranges from about twenty degrees (20°) toabout forty degrees (40°). However, for some aspects of the presentinvention, the acute angle θ could fall outside of this range.

The suction strainer assembly 42 is preferably configured so that anoperator can manually lift and remove each of the strainer baskets 158,and any coating material in the baskets 158, from the fluid manifold 156while standing on the ground alongside the vehicle 20. That is, theoperator can lift and remove each strainer basket 158, and any coatingmaterial in the basket 158, while standing next to the vehicle 20without the assistance of powered machinery. As a result, the suctionstrainer assembly 42 is particularly configured for convenient and quickmanual disposal of material caught in the suction strainer assembly 42.

The suction strainer assembly 42 is preferably fluidly connectedupstream of the pump 46 so that the strainer outlet 162 fluidlycommunicates with the pump inlet 152. In particular, the sprayingassembly 28 includes a pump intake manifold 176 (see FIG. 15) fluidlyconnected to the strainer outlet 162 of the suction strainer assembly 42and to the pump inlet 152.

The suction strainer assembly 42 is also fluidly connected to the tank26 via a tank discharge valve 177 and a tank discharge line 178 (seeFIGS. 13 and 14). The tank discharge line 178 fluidly communicates withthe valve 177 and with the fluid manifold 156.

The pump 46 draws coating material from the tank 26 and through thesuction strainer assembly 42, with material flowing through at least oneof the two suction strainer baskets 158.

The pressure strainer assembly 44 preferably includes a fluid manifold179 and two (2) pressure strainer baskets 180 (see FIG. 15). However,the pressure strainer assembly 44 could include an alternative number ofbaskets 180. For instance, the pressure strainer assembly 44 couldinclude more than two (2) baskets 158. The availability of multiplestrainer baskets 180 permits continued operation of the sprayingassembly 28 when one of the baskets 180 becomes full of aggregate andcongealed coating material (and restricts substantially all materialflow through the basket 180). If an alternative pressure strainerincludes more than two (2) baskets, the spraying assembly could continueto operate if multiple baskets become full of material (provided that atleast one basket is not full of material and permits material flowthrough the basket).

The fluid manifold 179 presents a strainer inlet 182 and a straineroutlet 184 of the pressure strainer assembly 44 (see FIG. 12). The fluidmanifold 179 also presents upstream and downstream chambers 186,188 onopposite sides of the baskets 182,184.

The fluid manifold 179 includes a diverter 189 that presents thestrainer inlet 182 and fluidly communicates with two (2) passages 190 ofthe manifold 179 (see FIG. 15). Thus, the chambers 186,188 fluidlycommunicate with each other and with the strainer inlet 182 via thediverter 189. The chambers 186,188 also fluidly communicate with thestrainer outlet 184.

The passages 190 extend between the chambers 186,188 in parallel withone another. That is, the passages 190 provide two separate paths forfluid to move between the strainer inlet 182 and the strainer outlet184.

The pressure strainer baskets 180 each preferably include a mesh body192 and a handle 194 (see FIG. 15). The mesh body 192 includes a sidewall 192 a and a bottom wall 192 b. That walls 192 a,192 b each comprisea mesh material that presents a plurality of openings. The openings eachdefine an opening size dimension that preferably ranges from about oneeighth inch (⅛″) to about three eighths of an inch (⅜″) and, morepreferably, is about three sixteenths of an inch ( 3/16″). The walls 192a,192 b cooperatively define a basket chamber 193 a. The baskets 180each preferably present an open top 193 b through which the flow ofcoating material passes into the basket chamber 193 a.

The basket chamber 193 a of each basket 180 preferably defines a basketvolume dimension that ranges from about one gallon to about fivegallons. However, for some aspects of the present invention, the basketvolume could fall outside of this range.

The pressure strainer baskets 180 are removably mounted in the fluidmanifold 179. More specifically, each pressure strainer basket 180 issecured in a corresponding one of the passages 168 so that fluid mustflow through at least one of the strainer baskets 180 to pass betweenthe chambers 186,188. The fluid manifold 179 includes strainer covers196 that can be selectively removed to permit the strainer baskets 180to be accessed and removed from the fluid manifold 179 (e.g., to permitcleaning of the strainer basket 180 and/or the inside of the fluidmanifold 179). Each of the illustrated strainer baskets 180 ispreferably removable independently of the other strainer basket 180.

The fluid manifold 179 and each strainer basket 180 cooperatively definea manifold axis A2 along which the strainer basket 180 is manuallyslidable into and out of the passage 190. In the illustrated embodiment,the manifold axis A2 is preferably angled upwardly from the lateraldirection at an acute angle (not shown), which is substantiallyidentical to an acute angle θ (see FIG. 13), so that an upper margin ofthe fluid manifold 179 is positioned outboard from a lower margin of thefluid manifold 179. The acute angle of the manifold axis A2 preferablyranges from about ten degrees (10°) to about fifty degrees (50°) and,more preferably, ranges from about twenty degrees (20°) to about fortydegrees (40°). However, for some aspects of the present invention, theacute angle could fall outside of this range.

Also in the illustrated strainer configuration, each pair of axes A1 aregenerally parallel to each other and each pair of axes A2 are generallyparallel to each other. Furthermore, the axes A1 are preferably parallelto the axes A2. However, the strainer assemblies 42,44 could bealternatively configured.

The pressure strainer assembly 44 is preferably configured so that anoperator can manually lift and remove each of the strainer baskets 180,and any coating material in the baskets 180, from the fluid manifold 179while standing on the ground alongside the vehicle 20. That is, theoperator can lift and remove each strainer basket 180, and any coatingmaterial in the basket 180, while standing next to the vehicle 20without the assistance of powered machinery. As a result, the pressurestrainer assembly 44 is particularly configured for convenient and quickmanual disposal of material caught in the pressure strainer assembly 42.

The pressure strainer assembly 44 is preferably fluidly connecteddownstream of the pump 46 so that the strainer inlet 182 is fluidlyconnected to the pump outlet 154 with a pump discharge tube 198.Specifically, the pump discharge tube 198 is fluidly connected to theoutlet 154 of the pump 46 and the inlet 182 of the pressure strainerassembly 44. Thus, the pump 46 is operable to pump coating material fromthe pump outlet 154 through the pressure strainer assembly 44, withmaterial flowing through at least one of the two pressure strainerbaskets 158.

While the illustrated spraying assembly 28 includes a single pump 46, itis within the scope of the present invention for the spraying assembly28 to include multiple pumps. For instance, as disclosed in theabove-incorporated ‘’xyz application, an alternative spraying assembly28 could include a pair of pumps that operate in parallel with oneanother and cooperatively move material through the strainer assemblies42,44.

It will be appreciated that one or both of the strainer assemblies 42,44could be alternatively configured without departing from the scope ofthe present invention. Furthermore, while the illustrated sprayingassembly 28 preferably includes both of the strainer assemblies 42,44,it is within the ambit of the present invention where only one of thestrainer assemblies 42,44 is used (e.g., for spraying operation).

Turning to FIG. 14, the outlet 184 of the illustrated pressure strainerassembly 44 fluidly communicates with a tank return inlet 200 and thespray boom 48. In particular, the vehicle 20 preferably includes apressurized material supply line 202, a supply manifold 204, and boomsupply valves 206 a,b. The line 202 extends rearwardly from the straineroutlet 184 and fluidly communicates with the supply manifold 204. Thesupply manifold 204 fluidly communicates with the tank return inlet 200and the boom supply valves 206 a,b.

The boom supply valves 206 a,b are configured to selectively permit theflow of pressurized coating material to the boom sections 100,102. Eachboom supply valve 206 a,b comprises a manually operable valve with afractional turn handle. The boom supply valves 206 a,b are fluidlyconnected to corresponding supply hoses 118 a,b to selectively controlthe flow of coating material from the supply manifold 204 tocorresponding supply hoses 118 a,b. In particular, the boom supply valve206 a is operable when opened to permit the flow of coating material tosupply hoses 118 a and to the chamber 110 a of the central boom section100. Boom supply valve 206 b is operable when opened to control the flowof coating material to supply hoses 118 b and to the chambers 110 b ofcorresponding extendable boom sections 102.

During spraying operation, the boom supply valves 206 a,b are allpreferably opened to permit coating material to flow to all of the boomsections 100,102. However, it is within the scope of the presentinvention where at least one of the boom supply valves 206 a,b is closedduring operation so that coating material is not supplied to at leastone of the boom sections 100,102.

The vehicle 20 is preferably configured to permit convenient andefficient filling of the tank 26 with coating material. Preferably, suchfilling is generally conducted prior to any spraying operation. Thevehicle 20 preferably includes a forward fill assembly 208 and an aftfill assembly 210 (see FIG. 14).

The aft fill assembly 210 preferably includes a stub line 212, a manualfill valve 214, and a coupler end 216 that presents a fill port 218 (seeFIG. 14). The stub line 212 is attached to and fluidly communicates withthe supply line 202. The fill valve 214 is shiftable between a closedposition and an open position (not shown).

The coupler end 216 is configured to be removably attached to a poweredmaterial filling station (not shown). The filling station includes asupply tank (not shown), a pump (not shown) that pumps coating materialfrom the supply tank, a fill supply hose (not shown) that dischargespressurized coating material from the pump. The fill supply hoseincludes a coupler end (not shown) that is coupled to the fill port 218by removably connecting the coupler end of the fill supply hose to thecoupler end 216 of the aft fill assembly 210. With the fill supply hoseconnected, coating material can be pumped from the supply tank to thesupply line 202.

To fill the tank 26 via the aft fill assembly 210, the coupler end ofthe fill supply hose is initially connected to the coupler end 216. Ifthe boom supply valves 206 a,b are open, the boom supply valves 206 a,bare preferably closed prior to operating the filling station.Optionally, the tank discharge valve 177 can also be closed prior tofilling the tank 26.

The operator can then operate the pump of the filling station so thatcoating material flows from the fill supply hose into the supply line202. The coating material can then travel through the supply manifold204 and into the tank 26.

The forward fill assembly 208 preferably includes a stub line 220, amanual fill valve 222, and a coupler end 224 that presents a fill port226 (see FIGS. 12 and 14). The stub line 220 is attached to and fluidlycommunicates with the pump intake manifold 176. The fill valve 222 isshiftable between a closed position and an open position (not shown).

The coupler end 224 is configured to be removably attached to anunpowered material filling station (not shown). The unpowered fillingstation includes a supply tank (not shown) and a fill supply hose (notshown) that discharges coating material from the supply tank. However,the unpowered filling station does not include a pump. Rather, the pump46 is preferably used to draw coating material from the supply tank ofthe filling station.

The fill supply hose includes a coupler end (not shown) that is coupledto the fill port 226 by removably connecting the coupler end of the fillsupply hose to the coupler end 224 of the forward fill assembly 208.With the fill supply hose connected, coating material can be pumped fromthe supply tank to the pump intake manifold 176.

To fill the tank 26 via the forward fill assembly 208, the coupler endof the fill supply hose is initially connected to the coupler end 224.If the boom supply valves 206 a,b are open, the boom supply valves 206a,b are preferably closed prior to operating the pump 46. Optionally,the tank discharge valve 177 can also be closed prior to filling thetank 26.

The operator can then operate the pump 46 so that coating material flowsfrom the supply tank, through the pump intake manifold 176, and into thepump 46. The coating material can then travel through the pressurestrainer assembly 44, the supply line 202, the supply manifold 204, andinto the tank 26.

The pump 46 and strainer assemblies 42,44 of spraying assembly 28 arepreferably configured to provide recirculation of coating materialcontained within the tank 26 and other components of the sprayingassembly 28. Coating material within the tank 26 is preferablyrecirculated through the system during a period when coating material isnot being sprayed. Recirculation restricts the coating material frombecoming clumped and/or from hardening within the system.

To recirculate coating material, the tank discharge valve 177 ispreferably opened. If the boom supply valves 206 a,b are open, the boomsupply valves 206 a,b are preferably closed prior to operating the pump46. If coating material is being recirculated without pumping additionalcoating material into the system, the fill valves of the fill assembliesare closed prior to operating the pump 46.

The operator can then operate the pump 46 so that coating material flowsfrom the tank discharge valve 177, through the tank discharge line 178,the suction strainer assembly 42, the pump intake manifold 176, the pump46, the pressure strainer assembly 44, the supply line 202, the supplymanifold 204, and back into the tank 26.

It is also possible to recirculate coating material within the systemwhile also pumping additional coating material into the system. For suchan operation, the fill valve 214,222 of the corresponding fill assembly208,210 used to permit the addition of coating material is opened topermit the introduction of additional coating material.

Control System

Turning to FIGS. 17 and 18, the spraying assembly 28 preferably includesthe control system 144 to open and close valves 122 of the central boomsection 100 and the extendable boom section 102. The control system 144is also used to set and maintain a predetermined application rate ofpavement coating material applied to a roadway. The control system 144preferably includes a processor element 228, a memory element 230, auser interface 232, a ground speed sensor 234, and a rotation speedsensor 236.

The control system 144 preferably includes hydraulic valves (not shown)that are operably coupled to, respectively, the boom shift cylinder 56,lift cylinder 90, boom extension cylinders 136, and valve cylinders 124.Thus, the control system 144 is configured to control the pistonposition for each of the cylinders 56,90,124,136.

As discussed above, the illustrated pump 46 is preferably calibrated topump a known mass or volume of material per pump count. The pump 46 canbe operated by the control system 144 to discharge, while operating at aset rotational speed, a volume of material into a container (not shown)for a predetermined number of pump counts. The mass of material in thecontainer is then measured (e.g., by weighing the container andmaterial) to produce a calibration scale factor. The calibration scalefactor is stored in the control system 144 and later used by the controlsystem 144 during operation to correlate pump count with the outputvolume (mass) of pavement coating material.

The ground speed sensor 234 is attached to the chassis frame 30 to sensethe ground travel speed of the vehicle 20. The sensor 234 preferablycomprises a radar sensor, although other vehicle speed sensors could beused without departing from the scope of the present invention.

The rotation speed sensor 236 is operably coupled to the pump 46 and isconfigured to sense the rotational speed of the pump 46. The illustratedpump 46 is preferably calibrated to pump a known volume of material forone complete pump revolution. Because the control system 144 isprogrammed to retain calibration data ratios of pumped material volumeper revolution of the pump, the processor can calculate the volumetricflow rate (and/or mass flow rate) of material transmitted by the pump 46as a function of the pump rotational speed.

The processor element 228 is operably coupled to the sensors 234,236 toreceive signals from the sensors corresponding to the sensed speedvalues. The processor element 228 is also preferably coupled to othersensors associated with the spraying system 28, and other components ofthe vehicle 20, to receive signals from those sensors about variousoperational parameters.

The user interface 232 is configured for an operator to input variouspredetermined operating parameters associated with a particular sprayingoperation. In the illustrated embodiment, the user interface 232preferably permits the operator to input the predetermined applicationrate of pavement coating material applied to the roadway. The userinterface 232 also preferably permits the operator to input apredetermined value of boom width B.

The illustrated user interface 232 is preferably installed in the cab 24and is accessible by the vehicle operator (e.g., when advancing thevehicle 20). However, the vehicle 20 also includes another userinterface that is similar to the user interface 232 and is mounted onthe rear deck 38 of the vehicle 20.

Based upon the predetermined value of boom width B, the control system144 is preferably programmed to move the extendable boom sections100,102 to corresponding positions so that the spray boom 48 providesthe corresponding boom width dimension. Additionally, the control system144 is also preferably programmed to keep corresponding valves 122 openso that corresponding spray nozzles 120 are engaged and operable tospray across the boom width B.

Preferably, the processor element 228 is operably coupled to the pump 46to control the rotational speed of the pump 46. The processor element228 calculates a pump rotation speed setpoint value as a function of theuser inputted values of predetermined application rate and boom width B.The processor element 228 also calculates the pump rotation speedsetpoint value as a function of the sensed value of ground speed fromthe ground speed sensor 234. As the operator increases or decreases theground speed of the vehicle 20, the processor element 228 automaticallyadjusts the rotational speed of the pump 46 to automatically maintainthe predetermined application rate of pavement coating material.

In use, prior to engaging the spraying assembly 28, the vehicle operatorpreferably sets the predetermined application rate of pavement coatingmaterial to be achieved by spraying a flow of pavement coating materialonto the roadway. Also prior to engaging the spraying assembly 28, theoperator preferably sets the boom width B. If the spray boom 48 is notat the boom width B, the spray boom 48 can be adjusted automatically bythe control system 144 or manually by the operator. The operator canthen engage the spraying assembly 28 and begin advancing the vehicle 20forwardly along the roadway.

As the vehicle 20 is being advanced, the control system 144 preferablydetermines the ground speed of the vehicle 20. In particular, theprocessor element 228 receives a ground speed signal from the groundspeed sensor 234.

Also, as the vehicle 20 is being advanced, the control system 144supplies power to and operates the pump 46 to discharge the flow ofpavement coating material onto the roadway through the engaged spraynozzles 120 (i.e., the spray nozzles 120 associated with valves 122 thatare kept open by the control system 144).

The pump 46 is preferably operated to maintain the predeterminedapplication rate by adjusting the volumetric flow rate (or mass flowrate) of the pump 46 in response to a change in the sensed ground speed.

If the operator adjusts the boom width B during the spraying operation,the control system 144 preferably automatically adjusts the volumetricflow rate (or mass flow rate) of the pump 46 to maintain thepredetermined application rate of coating material.

Although the above description presents features of preferredembodiments of the present invention, other preferred embodiments mayalso be created in keeping with the principles of the invention. Suchother preferred embodiments may, for instance, be provided with featuresdrawn from one or more of the embodiments described above. Yet further,such other preferred embodiments may include features from multipleembodiments described above, particularly where such features arecompatible for use together despite having been presented independentlyas part of separate embodiments in the above description.

The preferred forms of the invention described above are to be used asillustration only, and should not be utilized in a limiting sense ininterpreting the scope of the present invention. Obvious modificationsto the exemplary embodiments, as hereinabove set forth, could be readilymade by those skilled in the art without departing from the spirit ofthe present invention.

The inventors hereby state their intent to rely on the Doctrine ofEquivalents to determine and assess the reasonably fair scope of thepresent invention as pertains to any apparatus not materially departingfrom but outside the literal scope of the invention as set forth in thefollowing claims.

What is claimed is:
 1. A method of using a coating applicator vehicle to apply a flow of pavement coating material onto a roadway at a predetermined application rate, where the material includes a liquid emulsion and aggregate, said method comprising the steps of: (a) setting the predetermined application rate; (b) as the vehicle is being advanced, determining the ground speed of the vehicle; and (c) as the vehicle is being advanced, operating a pump to discharge the flow of pavement coating material onto the roadway through a series of spray nozzles, step (c) including the step of maintaining the predetermined application rate by adjusting the volumetric flow rate of the pump in response to a change in the determined ground speed.
 2. The method as claimed in claim 1, said spray nozzles cooperatively defining a spray application pattern along which the roadway is wetted with coating material, with the pattern presenting a width dimension measured transverse to the forward direction; and (d) adjusting a spray boom of the vehicle to change the width dimension.
 3. The method as claimed in claim 2, step (c) including the step of adjusting the volumetric flow rate of the pump in response to the change in the width dimension.
 4. The method as claimed in claim 3, said shiftable spray boom including a plurality of boom sections slidably attached to one another, each of said boom sections supporting and operable to fluidly communicate with a corresponding series of the spray nozzles, step (d) including the step of sliding the boom sections relative to each other along a common lateral direction.
 5. The method as claimed in claim 1, step (b) including the step of sensing the ground speed of the vehicle using a radar device.
 6. The method as claimed in claim 1; and (d) calibrating the pump by associating a range of volumetric flow rates with a corresponding range of pump rotational speeds.
 7. The method as claimed in claim 6, step (d) including the step of calibrating the pump without discharging pavement coating material from the spray nozzles.
 8. A coating applicator vehicle configured to selectively discharge a flow of pavement coating material onto a roadway at a predetermined application rate, where the material includes a liquid emulsion and aggregate, said coating applicator vehicle comprising: a rolling chassis operable to be advanced in a forward direction along the roadway; a powered spraying assembly supported by the rolling chassis and extending transversely to the forward direction to selectively discharge coating material along a lateral direction, said spraying assembly including a pump and a spray bar assembly, said spray bar assembly including a plurality of spray nozzles that selectively fluidly communicate with the pump to receive a flow of coating material from the spray boom and to discharge the flow of coating material, said spray nozzles cooperatively defining a spray application pattern along which the roadway is wetted with coating material, with the pattern presenting a width dimension measured transverse to the forward direction; and a control system including a speed sensor and a computer operably connected to the speed sensor to sense a ground speed of the vehicle, said computer operably connected to the pump to control a volumetric flow rate of coating material provided by the pump as a function of the sensed ground speed to apply coating material at the predetermined application rate.
 9. The coating applicator vehicle as claimed in claim 8, said spray bar assembly including a shiftable spray boom and a frame mounted relative to the chassis, said spray boom presenting an elongated chamber to receive and carry the coating material laterally, said spray nozzles supported by the spray boom and fluidly communicating with the chamber to receive a flow of the coating material from the spray boom and to discharge the coating material, said spray boom slidably supported by the frame and slidable relative to the frame in the lateral direction to shift the spray boom laterally relative to the rolling chassis, said control system including a position sensor to determine the lateral position of the spray boom relative to the rolling chassis.
 10. The coating applicator vehicle as claimed in claim 8, said pump comprising a positive displacement pump.
 11. The coating applicator vehicle as claimed in claim 10, said pump comprising a progressive cavity pump. 